OXIDATIVE STRESS INDUCES NF-KAPPA-B DNA-BINDING AND INDUCIBLE NOS MESSENGER-RNA IN HUMAN EPITHELIAL-CELLS

Free radicals generated by a partial reduction of O2 pose a serious threat to tissues and vital organs and cells. The major site of interaction between the lung and inhaled oxidants is the epithelium. We have examined the effect of pyrogallol, an O2- generator, on the ability of human epithelial cells to produce active DNA binding proteins and inducible nitric oxide synthase (iNOS) mRNA in cultured A549 epithelial cells. NFkB binding in the nuclei of these cells was determined by electrophoretic mobility shift assays. iNOS mRNA was measured using reverse transcription and PCR. There was a time- and concentration-dependent induction of NFkB binding, followed by a time and dose dependent increase in iNOS mRNA levels. These results suggest that in airways the initial response to oxidative stress may be to induce NFkB-responsive genes, such as iNOS, which may play an important role in defending the airway against oxidative stress. (C) 1994 Academic Press, Inc.